1. Field of the Invention
The present invention relates to a device for simply detecting not only the impact of an external force on a packed article during transport of commercial goods but also the direction of the external force. More particularly, the invention relates to a bidirectional shock sensor for proving the occurrence of an accident due to an inclination, tumbling, dropping impact or the like during the transportation of cargo and for proving who is responsible for the accident.
2. Background Art
A simple device, in which the inversion or tilt in a cargo during its transportation is detected in terms of the movement of a detector housed in a special container, was disclosed in the U.S. Pat. No. 3,688,734.
A device for showing receipt of predetermined shock was disclosed in another U.S. Pat. No. 4,068,613.
In these conventional devices, the measurement of an impulsive force is discontinuous, the equipment is complicated and has a large size, and its cost is therefore high. For that reason, the development of an impact detector of simple construction, low cost and high performance has been strongly needed.